ghoscht/xmclib
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
xmclib/CMSIS/Documentation/DSP/html/group__SQRT.html

284 lines
17 KiB
HTML
Raw Normal View History

Init xmclib
2024-10-17 17:09:59 +02:00
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<title>Square Root</title>
<title>CMSIS-DSP: Square Root</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<link href="cmsis.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<script type="text/javascript" src="printComponentTabs.js"></script>
<link href="navtree.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="resize.js"></script>
<script type="text/javascript" src="navtree.js"></script>
<script type="text/javascript">
$(document).ready(initResizable);
$(window).load(resizeHeight);
</script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/search.js"></script>
<script type="text/javascript">
$(document).ready(function() { searchBox.OnSelectItem(0); });
</script>
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 46px;">
<td id="projectlogo"><img alt="Logo" src="CMSIS_Logo_Final.png"/></td>
<td style="padding-left: 0.5em;">
<div id="projectname">CMSIS-DSP
&#160;<span id="projectnumber">Version 1.5.1</span>
</div>
<div id="projectbrief">CMSIS DSP Software Library</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<div id="CMSISnav" class="tabs1">
<ul class="tablist">
<script type="text/javascript">
<!--
writeComponentTabs.call(this);
//-->
</script>
</ul>
</div>
<!-- Generated by Doxygen 1.8.6 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
<div id="navrow1" class="tabs">
<ul class="tablist">
<li><a href="index.html"><span>Main&#160;Page</span></a></li>
<li><a href="pages.html"><span>Usage&#160;and&#160;Description</span></a></li>
<li><a href="modules.html"><span>Reference</span></a></li>
<li>
<div id="MSearchBox" class="MSearchBoxInactive">
<span class="left">
<img id="MSearchSelect" src="search/mag_sel.png"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
alt=""/>
<input type="text" id="MSearchField" value="Search" accesskey="S"
onfocus="searchBox.OnSearchFieldFocus(true)"
onblur="searchBox.OnSearchFieldFocus(false)"
onkeyup="searchBox.OnSearchFieldChange(event)"/>
</span><span class="right">
<a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
</span>
</div>
</li>
</ul>
</div>
</div><!-- top -->
<div id="side-nav" class="ui-resizable side-nav-resizable">
<div id="nav-tree">
<div id="nav-tree-contents">
<div id="nav-sync" class="sync"></div>
</div>
</div>
<div id="splitbar" style="-moz-user-select:none;"
class="ui-resizable-handle">
</div>
</div>
<script type="text/javascript">
$(document).ready(function(){initNavTree('group__SQRT.html','');});
</script>
<div id="doc-content">
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark">&#160;</span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark">&#160;</span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark">&#160;</span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark">&#160;</span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark">&#160;</span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark">&#160;</span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark">&#160;</span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark">&#160;</span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark">&#160;</span>Macros</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(9)"><span class="SelectionMark">&#160;</span>Groups</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(10)"><span class="SelectionMark">&#160;</span>Pages</a></div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div class="header">
<div class="summary">
<a href="#func-members">Functions</a> </div>
<div class="headertitle">
<div class="title">Square Root<div class="ingroups"><a class="el" href="group__groupFastMath.html">Fast Math Functions</a></div></div> </div>
</div><!--header-->
<div class="contents">
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:ga697d82c2747a3302cf44e7c9583da2e8"><td class="memItemLeft" align="right" valign="top">CMSIS_INLINE __STATIC_INLINE <br class="typebreak"/>
<a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga697d82c2747a3302cf44e7c9583da2e8">arm_sqrt_f32</a> (<a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> in, <a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *pOut)</td></tr>
<tr class="memdesc:ga697d82c2747a3302cf44e7c9583da2e8"><td class="mdescLeft">&#160;</td><td class="mdescRight">Floating-point square root function. <a href="#ga697d82c2747a3302cf44e7c9583da2e8">More...</a><br/></td></tr>
<tr class="separator:ga697d82c2747a3302cf44e7c9583da2e8"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ga119e25831e141d734d7ef10636670058"><td class="memItemLeft" align="right" valign="top"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga119e25831e141d734d7ef10636670058">arm_sqrt_q31</a> (<a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> in, <a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *pOut)</td></tr>
<tr class="memdesc:ga119e25831e141d734d7ef10636670058"><td class="mdescLeft">&#160;</td><td class="mdescRight">Q31 square root function. <a href="#ga119e25831e141d734d7ef10636670058">More...</a><br/></td></tr>
<tr class="separator:ga119e25831e141d734d7ef10636670058"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:ga5abe5ca724f3e15849662b03752c1238"><td class="memItemLeft" align="right" valign="top"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a>&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="group__SQRT.html#ga5abe5ca724f3e15849662b03752c1238">arm_sqrt_q15</a> (<a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> in, <a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *pOut)</td></tr>
<tr class="memdesc:ga5abe5ca724f3e15849662b03752c1238"><td class="mdescLeft">&#160;</td><td class="mdescRight">Q15 square root function. <a href="#ga5abe5ca724f3e15849662b03752c1238">More...</a><br/></td></tr>
<tr class="separator:ga5abe5ca724f3e15849662b03752c1238"><td class="memSeparator" colspan="2">&#160;</td></tr>
</table>
<a name="details" id="details"></a><h2 class="groupheader">Description</h2>
<p>Computes the square root of a number. There are separate functions for Q15, Q31, and floating-point data types. The square root function is computed using the Newton-Raphson algorithm. This is an iterative algorithm of the form: </p>
<pre>
x1 = x0 - f(x0)/f'(x0)
</pre><p> where <code>x1</code> is the current estimate, <code>x0</code> is the previous estimate, and <code>f'(x0)</code> is the derivative of <code>f()</code> evaluated at <code>x0</code>. For the square root function, the algorithm reduces to: </p>
<pre>
x0 = in/2 [initial guess]
x1 = 1/2 * ( x0 + in / x0) [each iteration]
</pre> <h2 class="groupheader">Function Documentation</h2>
<a class="anchor" id="ga697d82c2747a3302cf44e7c9583da2e8"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">CMSIS_INLINE __STATIC_INLINE <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_f32 </td>
<td>(</td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a>&#160;</td>
<td class="paramname"><em>in</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715">float32_t</a> *&#160;</td>
<td class="paramname"><em>pOut</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values. </dd></dl>
<p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p>
<p>Referenced by <a class="el" href="group__cmplx__mag.html#gae45024c497392cde2ae358a76d435213">arm_cmplx_mag_f32()</a>, <a class="el" href="group__RMS.html#ga0e3ab1b57da32d45388d1fa90d7fd88c">arm_rms_f32()</a>, and <a class="el" href="group__STD.html#ga4969b5b5f3d001377bc401a3ee99dfc2">arm_std_f32()</a>.</p>
</div>
</div>
<a class="anchor" id="ga5abe5ca724f3e15849662b03752c1238"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_q15 </td>
<td>(</td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a>&#160;</td>
<td class="paramname"><em>in</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea">q15_t</a> *&#160;</td>
<td class="paramname"><em>pOut</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF. </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values.</dd></dl>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x0000 to 0x7FFF. </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">*pOut</td><td>square root of input value. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if the input value is positive and ARM_MATH_ARGUMENT_ERROR if the input is negative. For negative inputs, the function returns *pOut = 0. </dd></dl>
<p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p>
<p>Referenced by <a class="el" href="group__cmplx__mag.html#ga0a4a8f77a6a51d9b3f3b9d729f85b7a4">arm_cmplx_mag_q15()</a>, <a class="el" href="group__RMS.html#gaf5b836b72dda9e5dfbbd17c7906fd13f">arm_rms_q15()</a>, and <a class="el" href="group__STD.html#gaf9d27afa9928ff28a63cd98ea9218a72">arm_std_q15()</a>.</p>
</div>
</div>
<a class="anchor" id="ga119e25831e141d734d7ef10636670058"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname"><a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6">arm_status</a> arm_sqrt_q31 </td>
<td>(</td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a>&#160;</td>
<td class="paramname"><em>in</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0">q31_t</a> *&#160;</td>
<td class="paramname"><em>pOut</em>&#160;</td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
</tr>
</table>
</div><div class="memdoc">
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x00000000 to 0x7FFFFFFF. </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">pOut</td><td>square root of input value. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if input value is positive value or ARM_MATH_ARGUMENT_ERROR if <code>in</code> is negative value and returns zero output for negative values.</dd></dl>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramdir">[in]</td><td class="paramname">in</td><td>input value. The range of the input value is [0 +1) or 0x00000000 to 0x7FFFFFFF. </td></tr>
<tr><td class="paramdir">[out]</td><td class="paramname">*pOut</td><td>square root of input value. </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The function returns ARM_MATH_SUCCESS if the input value is positive and ARM_MATH_ARGUMENT_ERROR if the input is negative. For negative inputs, the function returns *pOut = 0. </dd></dl>
<p>References <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a74897e18d4b8f62b12a7d8a01dd2bb35">ARM_MATH_ARGUMENT_ERROR</a>, and <a class="el" href="arm__math_8h.html#a5e459c6409dfcd2927bb8a57491d7cf6a9f8b2a10bd827fb4600e77d455902eb0">ARM_MATH_SUCCESS</a>.</p>
<p>Referenced by <a class="el" href="group__cmplx__mag.html#ga14f82f9230e9d96d5b9774e2fefcb7be">arm_cmplx_mag_q31()</a>, <a class="el" href="group__RMS.html#gae33015fda23fc44e7ead5e5ed7e8d314">arm_rms_q31()</a>, and <a class="el" href="group__STD.html#ga39495e74f96116178be085c9dc7742f5">arm_std_q31()</a>.</p>
</div>
</div>
</div><!-- contents -->
</div><!-- doc-content -->
<!-- start footer part -->
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
<ul>
<li class="footer">Generated on Wed Feb 8 2017 10:20:51 for CMSIS-DSP by ARM Ltd. All rights reserved.
<!--
<a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.6
-->
</li>
</ul>
</div>
</body>
</html>
Reference in a new issue Copy permalink